1. Technical Field
This invention relates to the transfer and pouring of molten metals such as the pouring of molten iron and steel from a refractory lined bottom pour transfer ladle and the practice of providing a ladle covering compound for heat insulation and absorption of non-metallics from the molten metal in the ladle.
2. Description of the Prior Art
The prior art compounds used in covering molten metals may be seen in U.S. Pat. Nos. 3,516,821, 3,607,234, 3,630,267, 4,066,446, 4,119,468 and 4,261,750. Similar disclosures may be seen U.S.S.R Patent 262,923 and Poland Patent No. 57370. The materials used in the compounds disclosed in these patents vary from the gas generating granules of carbon black and chalk and a wetting agent of U.S. Pat. No. 3,516,821, the Portland cement, fluorspar, Chamotte powder, soda ash and coke breeze of U.S. Pat. No. 3,607,234, the bloated (expanded) fire clay of U.S. Pat. No. 4,066,446, the iron ore, iron oxide, sodium nitrate, lime, sand and finely divided aluminum of U.S. Pat. No. 4,119,468, the vermiculite or pearlite ore and a minimum of acid treated graphite of U.S. Pat. No. 4,261,750 to the slag forming substances of the U.S.S.R and Poland Patents which are essentially Portland cement, fluorite, soda and feldspar.
Some of the prior art compounds depend on the incorporation of exothermic compounds such as disclosed in U.S. Pat. No. 4,261,750 and U.S. Pat. No. 3,630,267 discloses the application of a layer of molten slag of a specified thickness to the molten metal in the ladle.